A psychoacoustic principle of hearing and speech production is that an individual has a certain comfort rate at which they speak. This rate is also mediated by their own auditory system, i.e., a person talking hears themselves talking both internally and through their speech entering their ears. It is known in speech communication research that a talking individual establishes a speaking rate based on the hearing of his or her own speech which conforms to this internal comfort speaking rate. By adjusting the feedback speech rate between what the speaker is saying and what the speaker hears himself saying, it is possible to psychologically coerce the speaker to change their speaking rate. In effect, if language communicated by a speaker is slowed down and played back through headphones or a loudspeaker device to the speaker while the speaker is talking, the speaker will slow down his speaking rate in an attempt to maintain the speaking rate they are hearing. This is the result of a self-correcting mechanism in the motor language model of speech production, which balances the rate at which speech is spoken to the rate at which that speech is heard internally. The motor language model describes speech production as the coordination of muscular actions in the respiratory, laryngeal, and vocal tract systems. It is a feedback mechanism, which attempts to minimize the speaking rate difference between what is heard and what is being spoken. Motor control is described as the planning and coordination of muscle movements of the articulatory gestures in speech production from sensory feedback.
The Lombard effect in speech describes how people change their speech in noisy surroundings with the most obvious change to simply speak louder. The Lombard effect is one example of self-auditory feedback, which psychologically encourages a talker to speak louder than the level of the surrounding sounds they are hearing. The talker places emphasis on certain sections of the words to improve the discernibility and hence intelligibility of the speech. Consider when you speak to someone at a concert; you “pronounce” words differently. Many algorithms have tried to capture this behavior to improve the intelligibility of reproduced speech in voice communication systems. None have been able to do so yet. The psychological effect of hearing background noise while speaking is a feedback mechanism, which typically compels a person speaking to speak with different articulation.
Similarly, there are speech/hearing devices in which speech is captured through a microphone and played back to the talker while they are talking. These are seen on sports newscasts where a hearing device lets the talker hear what they are saying. Additionally, this principal has been used intentionally with a delay in the hearing device playback for people with stuttering disabilities. Studies have shown that speech played back to a stuttering talker while they are talking can lessen the number of their stutters. The psychological feedback mechanism with the delay allows them to hear themselves just prior to formulation of the articulator gestures. This additional delay smoothes their speaking.
Therefore a need exists to overcome the problems with the prior art as discussed above.